The invention provides a solar silicon slice cleaning agent, and belongs to the field of cleaning agents for electronic industry. The cleaning agent of the invention mainly comprises sodium hydroxide, sodium carbonate, sodium silicate, disodium edentate, sodium dodecyl benzene sulfonate, sodium dioctyl sulfosuccinate, polyethylene glycol, Tween-80, OP-10, triethanolamine, anhydrous alcohol or normal butyl alcohol or isopropyl alcohol or a composition of anhydrous alcohol, normal butyl alcohol or isopropyl alcohol, and deionized water. The cleaning agent is alkaline, does not contain sulfur and phosphorus additives, and when used as alone, has the advantages of good decontamination and cleaning property, low slice-returning rate, long service cycle, no corrosion to silicon slice, low operational requirements in use, easy treatment of treated waste oil and sewage, and the suitability for manual, semi-automatic and full automatic ultrasonic cleaning production lines of various process; in addition, the cleaning rate is over 99 percent, the slice-returning rate is close to zero, and the cost of the process of the invention is one tenth to one twentieth of that of the conventional cleaning process.